Method of terminating a heating glass structure



y 21, 1968 R. LECLERCQ 3,383,762

METHOD OF TERMINATING A HEATING GLASS STRUCTURE Filed Jan. 11, 1965 5 Sheets-Sheet 1 5 2a. FIG I 5 5 ,Gczzz: W W

y 21, 1968 R. LECLERCQ 3,383,762

METHOD OF TERMINATING A HEATING GLASS STRUCTURE Filed Jan. 11, 1965 5 Sheets-Sheet 2 y 1968 R. LECLERCQ 3,383,762

METHOD OF TERMINATING A HEATING GLASS STRUCTURE Filed Jan. 11, 1965 5 Sheets-Sheet is FIG-7 United States Patent 0 3,383,762 METHOD OF TERMINATING A HEATING GLASS STRUCTURE Ren Leclercq, Antony, Seine, France, assignor to Jean- Pierre de Montmollin and Ren Gugger, both of Neuchatel, Switzerland Filed Jan. 11, 1965, Ser. No. 424,597 Claims priority, application France, Jan. 15, 1964,

7 Claims. cl. 29-611 ABSTRACT OF THE DISCLGSURE A method for the production of a heating glass structure and the product thereof. The method comprises the steps of bonding a heating netting of resistance wires to the surface of a plastic carrier, and attaching the heating netting to a glass plate with the resistance wires in direct contact with the inner surface of said glass plate, and with a port-ion of the carrier extending past the glass plate, said extending portion of the carrier carrying the end portions of some, but not all, of the resistance wires. Electrode means are then attached to the surface of the carrier opposite that surface to which the heating netting is bonded, part of the extending portion of the carrier is cut away and the remainder is folded back across itself so that the resistance wires which are extending fall across the electrode means to which they are attached. A second glass plate is then applied over the carrier and bonded thereto.

The present invention relates to an improved heating glas structure as well as to an improved method for the production thereof.

With heating glasses or panes which embrace a socalled netting composed of metal wires providing electric resistors heated by the Joule-effect, these resistors are disposed in parallel between two current lead-in wires or the like formed by thin, conductive bands or strips arranged in the region of two oppositely situated edges of the heating glass. In such an arrangement the borders or edges of the glass structure are not subjected to the heating effect of the resistors. More specifically, this heating effect is not effective at a width of the glass which corresponds to the distance between the border of the glass and the conductive strips, increased by the width of the conductive strips themselves.

The width of this non-heated zone which can be quite appreciable reduces to the same degree the useful surface of the glass. Furthermore, the temperature differences between the cold borders or edges and the region heated by the resistors can be of great importance under certain applications of use of the glass, for example in the case of dc-frosting of airplane windows. The differences in elongation resulting from such temperature differences can lead to rupture of the heating wires at the region of their junction with the conductive strips.

Accordingly, it is an important object of the present invention to provide an improved method for the production of heating glass structures of the type described as well as to improved heating glass structures which overcome the previously recited disadvantages.

A further important object of this invention relates to the manufacture of an improved heating glass structure of the hereinmentioned type wherein the heating wires are arranged such that it is possible to considerably reduce the non-heated portions of the glass structure to a minimum as well as to considerably free the heating wires from the stresses brought about by possible temperature differences.

Generally speaking, the improved heating glass struc- 3,383,762 Patented May 21, 1968 ice ture developed according to the invention is characterized by the features that, the heating wires extend from their end soldered with one of the current lead-in wires or electrodes in a direction towards the edge lying closest to the aforesaid electrode and, more specifically, extend at least into a portion of the space between such electrode and the mentioned edge. In this space such heating wires are flexed back through an angle of substantially 180, in order then to finally extend in a direction towards the opposite edge of the glass structure. In so doing, these heating wires move past the aforesaid electrode without coming into contact with such.

It should be appreciated that the described arrangement of the heating wire netting according to the invention provides a number of different advantages, of which the more noteworthy ones will now be briefly considered: It is to be realized that the loop which a given wire forms between the electrode and the neighboring edge of the glass structure imparts to such wire a certain flexibility or ductility which increases its resistance to mechanical stresses resulting from temperature differences. On the other hand, the portion of the wire forming the loop as well as the portion of the wire which is directed back past the electrode without coming into electrical contact with such, deliver calories in this marginal zone of the glass structure which, as already mentioned, are not heated without carrying into effect the teachings of the present invention.

The heating glass structure designed according to the teachings of the present invention can be realized in a number of different ways. A particularly advantageous manner of fabrication, which constitutes a further aspect of the subject invention, will now be considered in detail. According to the inventive method for the manufacture of the aforementioned heating glass structure it will be appreciated that in a first stage the heating netting is produced which is embedded upon the surface of a carrier composed of a transparent synthetic resin or plastic foil, such as for example polyvinyl butyral. The heating netting prepared in this manner is bonded upon a glass plate which forms the outer or external element of the heating glass structure, whereby the resistance wires should come into direct contact with the inner surface of this aforesaid element. Both of the current infced electrodes are arranged at the side of the plastic foil opposite the resistance wires, which in this manner are then insulated from the heating netting through the thickness of the plastic foil. Then the foil is cut at both edges of the heating glass structure and a plastic strip is pulled off substantially parallel to each electrode. By bending back the edge or edges of the heating netting through 180 towards the inside the resistance wires are brought into contact with the associated current delivery electrode to which they are soldered. The heating glass structure is cor .plcted by mounting a second glass plate which should form the inner surface element of the glass structure.

Other features, objects and advantages of the invention will become apparent by reference to the following detailed description and drawings in which:

FIGURE 1 is a fragmentary perspective view depicting details of the preliminary preparation of the heating netting;

FIGURE 2 is a top plan view of the arrangement of FIGURE 1;

FIGURES 3, 3a, 4 and 5 schematically illustrate different successive stages of the assembly of the heating netting in the glass structure;

FIGURE 6 is a fragmentary plan view of the completed glass structure; "and FIGURE 7 is a fragmentary, elevational cross-sectional view through the completed glass structure of FIGURE 6.

Describing now the drawings it will be understood that in the illustrated embodiment it is intended to produce Preparation of the healing netting Considering now FIGURE 1 it will be seen that a foil 2 formed of transparent plastic, such as for instance polyvinyl butyral, is placed upon a planar support, for example a glass plate 1 which is larger than the glass structure which is to be produced. This foil 2 is bonded with the edges of the glass plate 1 by means of heat, however, is separated from the aforesaid glass plate 1 in the central region, in other words beneath the heating netting 6 to "be providedas will be explained shortlyby means of a very thin foil 3 formed of a substance such as that which is known on the market under the trademark Mylar. It will be appreciated that this separation foil 3 prevents bonding of the polyvinyl butyral foil 2 with the glass plate 1 in this central region, which in consideration of the subsequent process steps should permit easy separation of such polyvinyl butyral foil 2 carrying the heating netting 6. The glass support plate 1 is provided with a crack or break line 4 (FIGURE 2) which designates the periphery or contour of the glass structure to be manufactured and which simplifies arrangement of the heating netting 6, as such will further be considered shortly.

It will be further seen that two outs 5a and 5b are undertaken at the entire thickness of the polyvinyl butyral foil 2. Such cuts 5a and 5b end approximately at the region of the break line 4 provided at the glass support plate 1. Thereafter, and according to a known process, in the next machine the heating wire netting is placed upon the polyvinyl butyral foil 2, the latter thus serving as carrier. With the exception of the zone 2:: bounded by the cuts 5a and 5b of the mentioned carrier foil 2 at which the wires 6c of the heating netting 6 should not be bonded with the butyral, these wires are bonded by the action of heat with the polyvinyl butyral foil 2. As can be readily ascertained from the drawings, the heating wires 6c are arranged in undulatory or sinusoidal form, the amplitude of which are for example amounts to 0.3 to 0.4 millimeter and the wave length of which can amount to 1 millimeter. By 'way of example, in the illustrated embodiment the resistance wires 6c possess a spacing from one another amounting to about 0.6 to 0.8 millimeter. Furthermore, by way of example, it is possible to use Wires formed of tunsten, ferro-nickel or copper, with a diameter of to 13 microns, in the event it is desired to develop greater electrical power in the order of magnitude of 50 to 80 watts per square decimeter.

Moreover, from FIGURES 1 and 2 it will be seen that certain wires, such as those designated by reference characters 6a and 6b, of the heating netting 6 are elongated to extend past the cut 512, whereas others are bent back in order to build a respective loop 6d at the other side of the cut 5a. After the heating netting 6 is placed upon the carrier foil 2 formed of polyvinyl butyral the latter is removed from the glass plate 1 serving as support. Thereafter, the foil 2 can be cut along the lines 7 at both ends of the cuts 50. and 5b, as best seen by referring to FEGURE 2, and the strip 2b bounded by the walls of such cuts is removed.

Mounting of the heating netting upon the outer plate of the glass structure By referring to FIGURE 3 it will be seen that the heating netting 6 carried by the foil 2 formed of polyvinyl butyral is turned over and placed upon the external or outer plate 8 of the glass structure. The heating netting '6 is turned over in order that the wires 60 thereof come into direct contact with the inner surface of the external plate '8, thereby favoring heating thereof. After correct centering of the polyvinyl butyral foil 2 carrying the heating netting 6 with respect to the periphery of the plate 8 this foil is spatially fixed at individual points, such as designated by reference numeral '9, by the action of heat. The protruding polyvinyl butyral foil 2 is then cut in accordance with the shape 10 of the outer plate '8.

It will be further apparent by inspecting FIGURE 3 that assembly of the butyral foil 2 upon the plate 8 takes place in such a manner that the edge 8a of the aforesaid plate 8 extends approximately through the middle of the zone 2a of the strip 212 removed from between the cuts 5a and 5/). Also, the butyral foil 2 is then out along the lines 11 between its edge and the associated out line 7 (FIGURE 3a). It will thus be appreciated that the fabrication procedure described up to the present then provides a structure such as depicted in FIGURE 4, in which the wires 6c are illustrated in phantom lines (as also in FIGURE 3) because they are located at the underside of the polyvinyl butyral foil 2.

Thereafter, a lead-in wire or electrode 12 is bonded to the polyvinyl butyral foil 2 by the action of heat, this lead-in wire being formed of a tin plated copper strip or band 12. It will be appreciated that in the illustrated embodiment the strip 12 is arranged at a distance of approximately 1 to 2 millimeters from the cut line 5a.

Soldering of the heating wires with the electrode The protruding or extending polyvinyl butyral strip 20 of the carrier foil 2 which carries the ends of the heating wires 6a, 6b, etc. which extend past the cut line 5b (FIGURE 4) is then tilted back and by pivoting about the cut line 5a (FIGURE 5) or a line extending parallel to this cut line and nearer the neighboring edge of the plate 8 is flipped back upon the remainder of the polyvinyl butyral foil 2. These wires are then soldered with the electrode 12, for instance at the locations designated 13, 13, 13" and thereafter are separated at locations 14, 14, 14", whereafter this flipped-back butyral strip 20 which carries the ends 6a, 611, etc., of the wires is removed. Then a second strip 15 formed of tin plated copper is soldered via the wires to the electrode 12. In order to ensure for a continuity of the polyvinyl butyral foil 2 at the region '16, a correspondingly shaped polyvinyl butyral strip 16a is cut and placed at this location.

Of course, it will be appreciated and should be clearly understood that all of these manufacturing steps are undertaken at two opposite edges of the glass structure. Now, only the gass plate 18 must be assembled which should form the inner plate of the heating glass structure. This glass plate '18 is previously provided with a polyvinyl butyral foil 17. The unit 17, 18 is then positively centered and by the action of heat is bonded to the heating plate produced in accordance with the aforedescribed process step. In FIGURE 6 there is depicted a plan view of the completed glass structure. By referring to FIGURE 7, which shows a section through the thus produced glass structure, it is possible to readily ascertain that the heating wires 6 are directly in contact with the external or outer plate 8, whereas the electrodes 12, 15 are completely enclosed in polyvinyl butyral. On the other hand, from an inspection of FIGURE 6 it will be seen that the lead-in conductors or electrodes 12, 15 are arranged in a zone of the glass structure which is partially covered by the heating netting 6, which was not the case with the previous assembly of such glass structure according to prior art methods. It is also to be understood that the se quence of steps need not in every case be as outlined herein. For instance, the strip 211 can be cut after placing of the foil 2 upon the plate 8.

While there is shown and described at present preferred embodiment of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims.

What is claimed is:

1. Method for the production of a heating glass structure of the type described comprising the steps of: bonding a heating netting incorporating resistance wires to the surface of a carrier, then attaching the heating netting to a glass plate providing the external element of the heating glass structure such that said resistance wires are directly in contact with the inner surface of said glass plate, a portion of the carrier supporting said heating netting extending past at least one edge of said glass plate, a number of said resistance wires having end portions carried by said extending portion of said carrier, applying electrode means to the surface of said carrier opposite the surface to which said heating netting is bonded, cutting a strip from said extending portion of said carrier such that the bounding walls of the recess formed by cutting said strip are disposed at opposite sides of said one edge of said glass plate, then bending the extending portion of said carrier back towards said opposite edge of said glass plate to bring said end portions of said number of resistance wires into contact with said electrode means, then bonding said cont-acting end portions to said electrode means, and applying a second glass plate providing the inner surface element of said heating glass structure to said carrier to complete fabrication of said heating glass structure.

2. Method for the production of a heating glass structure of the type described comprising the steps of: bonding a substantial portion of heating netting incorporating resistance Wires to the surface of a carrier, then attaching the carrier supporting the heating netting to a glass plate providing the external element of the heating glass structure such that said resistance wires are directly in contact with the inner surface of said glass plate, a portion of the carrier supporting said heating netting extending past at least one edge of said glass plate, a number of said resistance wires having end portions which are carried by said extending portion of said carrier, applying electrode means to the surface of said carrier opposite the surface to which said heating netting is bonded, then bending the extending portion of said carrier back towards said opposite edge of said glass plate through an angle of substantially 180 to bring said end portions of said number of resistance wires into contact with said electrode means, then bonding said contacting end portions to said electrode means, and applying a second glass plate providing the inner surface element of said heating glass structure.

3. Method for the production of a heating glass structure of the type described comprising the steps of:

(a) bonding a heating netting incorporating resistance wires with the exception of given portions of a number of said resistance wires disposed between two spaced out lines of a carrier to the surface of said carrier,

(b) then connecting the carrier supporting the heating netting to a glass plate providing the external element of the heating glass structure such that said resistance wires are directly in contact with the inner surface of said glass plate, a portion of the carrier supporting said heating netting extending past at least one edge of said glass plate, said number of said resistance wires having end portions carried by said extending portion of said carrier,

(c) applying electrode means to the surface of said carrier opposite the surface to which said heating netting is bonded and adjacent yet in spaced relation from said one edge,

(d) cutting a strip from said extending portion of said carrier overlying said given portions of said number of resistance wires such that the bounding walls of the recess formed by cutting said strip are disposed at opposite sides of said one edge of said glass plate,

(e) cutting said carrier to the contour of said glass plate such that said extending portion of said carrier is connected with the remainder of said carrier overlying said glass plate by said end portions of said number of resistance wires,

(t) then bending the extending portion of said carrier back towards said opposite edge of said glass plate through an angle of approximately to bring said end portions of said number of resistance wires into contact with said electrode means,

(g) then bonding said contacting end portions to said electrode means,

(h) removing said bent back extending portion of said carrier, and

(i) applying a second glass plate providing the inner surface element of said heating glass structure onto said carrier.

4. Method for the production of a heating glass structure as described in claim 3 wherein said carrier is a foil formed of transparent plastic.

5. Method for the production of a heating glass struc ture as described in claim 4 wherein said transparent plastic is polyvinyl butyral.

6. Method for the production of a heating glass structure as described in claim 3 including the step of applying a further electrode means onto said end portions of said number of resistance wires prior to application of said second glass plate.

7. Method for the production of a heating glass structure as described in claim 3 wherein said carrier extends past the other opopsitely situated edge of said glass plate providing said external element, a further number of said resistance wires having end portions carried by said portion of said carrier extending past said other oppositely situated edge, and also carrying out steps (c) to (h) with respect to the opposite edge of said glass plate and said extending portion of said carrier thereof.

References Cited UNITED STATES PATENTS 1,916,895 7/1933 Rowe 2l9-203 2,526,327 10/1950 Carlson 219--203 X 2,827,538 3/1958 Polis et a1 219-522 X 3,288,983 11/1966 Lear 219--203 X 3,313,920 4/1967 Gallez 2l9203 X JOHN F. CAMPBELL, Primary Examiner.

RICHARD M. WOOD, Examiner.

V. Y. MAYEWSKY, J. CLINE, Assistant Examiners. 

